Ok i have a 1986 with the 22r motor. The truck started misfiring/bucking under load but if i keep driving it the problem goes away after about 5 miles. The problem has gotten progressively worse to where now it just growls when i try to accelerate but it still eventually gets better and goes away after i drive about 5 miles. ITS NOT COLD OUT EITHER I LIVE IN AZ ITS 100+ EVERY DAY. IT USE TO REV FINE WHEN IT WAS JUST BUCKING BUT NOW THE REV IS AFFECTED BY THE GROWL BUT ONLY IF U REV IT UP FAST IT WILL STILL REV FINE IF U DO IT SLOWLY. Also some days the truck runs great but then the next day it will be back to doing it again. When it is having the issue it smells rich which could mean either weak spark or too much fuel. It doesnt matter what the temp is outside or the humidity the truck might run good or it might run like ˟˟˟˟!! The fact that the problem isnt every day and that it goes away after a few miles is very confusing. I dont think its fuel related because it goes away after the motor gets good and hot and motors require less fuel when they are hot so it would be the opposite of what its doing.
Please help me i really cant figure this out.

Things ive replaced

plugs
wires
cap and rotor
coil
fuel filter

 

Bump... Anyone have any suggestions?

 

Vaccum leak?

 

EGR valve opening too early and or stuck open at times..?

Choke not operating properly...?

Restricted intake air flow..?

Leaking Auxiliary Accelerator Pump(AAP) diaphragm...?

Incorrect fuel pressure...?

Fuel pump...?

 

Thanks guys but it has a weber on it with a electric fuel pump and regulator and the psi is in spec... Egr is eliminated, aap is working good but I will check the choke out its hard to check tho because the temp here never goes under 90

 

Intermediate coil/igniter assembly fault..?

 

Update truck great for 4 days then when I left work last night it was right back to running crappy but this time it didn't get better with time until I turned the truck off and restarted it and it started getting better and eventually ran fine again